Apparatus for treating coal briquettes and the like



June 22, 1965 a. KARDAUN ETAL 3,190,814

APPARATUS FOR TREATING COAL BRIQUETTES AND THE LIKE Filed June 21, 1961United States Patent 0 3,1gli,3li i- APPARATUS FGR TREA'HNG CUALBRIQUETTES AND THE} LlKlE Georg Kardann and Thecdonr H. van der Gugten,Stein, Netheriands, assignors to @tarniearhon N.V., Heerien, Netherlandsl iied June 21, 19611, Ser. No. 118,728 Ciaims priority, applicaticnNetherlands, June 23, 1960,

8 'tilaiins. (Cl. 262-129) This invention relates to apparatuses for thegas treatment of coal briquettes in a container or the like having aperforated bottom wall for the passage of the gases. In apparatuses ofthis character, coal briquettes which have been made with the aid of abinder, such as tar or pitch, are subjected to oxidation by treatmentwith oxygen-con taining gases in order to obtain smokeless briquettes.

It isa well-known practice to treat the briquettes by discharging theminto a container mounted on a wagon, the wagon being run through atunnel furnace, successively passing through various oxidation zones andcooling zones. gases are properly controlled in the oxidation zone sothat the binder in the briquettes is treated, but the coal takes littlepart in the reaction. The'heat generated during i this treatment isremoved by the gases flowing through the bed of briquettes and theamount of gases necessary for this purpose, of course, depends upon thequantity of briquettes to be treated.

In order to pass these gases through the briquette bed at the desiredrate, a dilference in pressure between the spaces on either side of thebriquette bed is provided, the magnitude of which is determined by theresistance of the bed, i.e. the bed height.

Such installations or apparatuses known in the prior art are providedwith means for sealing the boxes from the walls thereof during travelthrough the furnace; however, such sealing means between the travelingwagons and fixed ovenwalls cannot be constructed to allow substantialdiiferences in pressure. In order that a sufficient amount of gases maybe passed through the briquettes, notwithstanding the low pressuredifferential, the bri quette layer must not exceed a pre-determinedheight which, in turn, means that the containers are sharply limited intheir capacity. For example, containers of this character generally havea capacity of approximately three tons, and the resistance offered bythe smaller briquettes being greater than that of the larger briquettes,the height of a bed of small briquettes is correspondingly lower.

Further shortcomings of such prior art means for treating briquettesrelates to the undesirable heat losses due to the small capacity of thecontainers. Likewise, the amount of time consumed for starting andstopping the installation is relatively great. Thus, such an arrangementis undesirable in instances where the working periods are short, as inthe mining industry where coal mining and preparation generally takeplace only during the day. Additionally, in order to regulate thedilTerent phases of such prior art treating methods and apparatusesinorder to obtain proper adjustments, a large number of measuring andcontrol instruments are necessarily required.

01": considerable importance in the treatment of the briquettes is theheight of the briquette bed; and, accordingly, the container issubstantially the same height in all places. Otherwise the resistance ofthe gas flow will be great where the height of the briquette bed islarge and likewise small where the height of the bed is relativelysmall. Consequently, there is an insufficient heat discharge in the areaof a thick briquette bed resulting in a temperature rise and danger ofthe briquettes beginning to burn. Accordingly, particular care is takento fill the The temperature and the oxygen content of the tion, and isso mounted that the angle between the bottomv wall and the horizontal issubstantially equal to the natural slope of the briquettes to betreated. The box is providedwith one or more filling openings near itshighest point andwith one or more discharge openings near the lowestpoint thereof. 1 A still further object of this invention is to providean apparatus for treating coal briquettes wherein a fixed container isutilized, thereby obviating the requirement for movable seals. By virtueof this construction, the gas flow can be accurately adjusted, andgreater differences in pressure and larger amounts of gas can besupplied than in the prior art apparatuses of the characterdescribed.Accordingly, a thicker briquette bed maybe utilized, "the container inthe apparatuses according to this invention having a capacity in theorder of 40 tons. V a

A still further objective of the invention is to provide an apparatusfor treating coal briquettes which is of considerably reduced size for agiven capacity than heretofore known. Accordingly, the constructioncosts are considerably .reduced and the apparatus occupies less space.

Additionally, superior heat economy is obtained by virtue of the largeunits even with the waste heat being regenerated. As the container is anindependent unit and the condition of its contents is not dependent onthat of other charges, if any, there is no undesirable loss by virtue ofstarting orstopping time and the number of measuring and control devicesis also reduced.

Likewise, this invention contemplates the provision of means foraltering the angle between the container bottom wall and the horizontalfor accurate adjustment to the natural slope of the briquettes to betreated.

A still further object of this invention is to provide an apparatus fortreating briquettes wherein a briquette container is provided with abottom wall havingan angle conforming with the natural slope of thebriquettes, and also being provided means to minimize the danger ofdamage to the briquettes as they are being filled into the container,there being provided means for reducingthe rate of fall of thebriquettes during the filling of the container.

To this end, a number of grates may be mounted under the feed opening ofthe container so that the briquettes .tall from one grate to another.The briquettes thereby supplied are rolled over the grates andgraduially fill the lower part of the container and when this portion ofthe container is filled to the grates, the briquetteswill flow over theback edges thereof into the top part of the portion which is locatedbehind the grateuntil, at last the box is completely filled.

Damage to the briquettes may be further obviated by suspending chains orflexible members of thecontainerat the lower edges of the grates, thefall of the briquettes from one grate to another therebybeingbroken. Thedistance from the chains to the lower edges of the grates may be suchthat the chains will only turn aside toallow briquettes to pass as acertain lateral forceisjexerted on the chains. As a result'therewillalways be a thin layer of briquettes on the auxiliary. grates so thatthebriquettes supplied will not immediately fall thereon. .The successiveedge of the following grate.

Further, according to this invention, means are provided to preventdamage to the bottom briquettes in the container by the weight of thebriquette bed resting on them. At the hightemperature prevailing duringthe treatment, the strength of the briquettes is so low that, for

instance, briquettesweighing. 20 grams, which have been produced withthe aid of pitch as a binder, become damagedat a pressure exceeding 0.8kg. 'For this reason,

'the briquette bed must not attain such a thickness that the weightresting on the bottom briquettes exceeds this critical value. It hasbeen found. that, measured in the vertical 'direction, approximately onemeter'is the limit of thickness which does not cause damage to thebriquettes owing to the static pressure. The pressure exerted by'thebriqquette bed is partly absorbed by the side walls of the box.

According to this invention, partitions running parallel to the sidewalls are mounted in the box, so that part of the pressure exerted bythe material which is absorbed by the vertical walls, is increased manytimes, and the pressure on the briquettes in the lowest layer isdecreased accordingly. It has been found that with a bed thickness of1.5

meters or-more, the pressure on the bottom briquettes will not exceedthe compressive strength and no deformation of the briquettes will occurif the distance between the partitions does not exceed 20-25 cm.

Still further objects, advantages, and novel features of this inventionwill become apparent in the specification and claims, taken with theaccompanying drawing.

In the drawing: 7

FIGURE 1' is an elevation view, generally in section an apparatus forgas treatment of briquettes according to this invention;

FIGURE 2 is a view taken substantially along line 2-2 in FIGURE 1;

FIGURE 3 is an elevation section view of a modified container accordingto this invention;

FIGURE 4 is still another embodiment of a container according to thiscontainer; and

FIGURE is a plot of the force K exerted on the lower briquettesversus-the thickness H of the briquette bed.

Referring now to the drawing, there is shown in FIG- URE 1 an apparatuswhich includes an annular conduit 1 of appropriate construction, theconduit 1 carrying an axial blower 2 providing a flow of. gases in thedirection indicated by the arrows. A combustion burner 3 is operativelymounted in communication with the conduit 1 to supply combustion gasesthereto.

Mounted in anenlarged portion of conduit 1 is a fixed container 4according to this invention, which contains a bed of coal-briquettes, aswill become apparent. The quantity of gas corresponding with thequantity supplied bythe combustion installation is discharged fromtheconduit 1 through an exhaust conduit 5 at the upper end thereof, theexhaust conduit 5 having a regulating valve 6 mounted therein.

As necessary, an oxygen-containing gas, such as air and/or a coolingmedium, such as water, are added as necessary to the gas via conduits 7,8 prior to .the recirculation of the gas.

The container- 4 bridges the entire area of the enlarged portion of thechannel 1 so that the gases must flow therethrough. To thisend, thebottom wall 9 of the container posed. at an angle, of approximately 40to the horizontal corresponding to the natural slope of the briquettestobe treated. ,A fillingopening: 10 is disposed in the highest point ofthe container 4v in order to insure the briquettes have a slope shown bythe line 11, the slope 11 of the .bed of briquettes fed into thecontainer 4 thereby being gen erally. parallel to the bottom'wall 9 somebriquette bed thickness is the same. throughout the container 4..Consequently, the resistance to gas flow will be more or less equalthroughout the area occupied by the container 4, as is apparent.

Referring to FIGURE 2, the container 4 is dividedinto l 4 is in theshape of a grate. .This bottom wall 9 is dis- I a number of equallyspaced components or compartments 13 by spaced-apart parallel partitions12, the partitions 12 being mounted approximately 20 cm. from oneanother. Consequently, the pressure of the bottom briquette ismaintainedbelow the maximum allowable value. That is, the function of thesepartition walls resides in their absorbing a portion of the forceexerted by the column of material which would otherwise act on the lowerbriquettes on the bottom wall. In the plot of FIG- URE 5, K indicatesthe force exerted on the lower briquettes, 'H indicates the thickness ofthe bed, and It, indicates the force at which the briquettes will break.

Curve A shows the relation between the force K and the thickness H ofthe bed when no partition walls are used. The plot shows that thethickness of the bed has to be smaller than I1 to avoid damage to thebriquettes. When adding partition walls according to the invention, theincrease of the force K is smaller when the thickness of the bedincreases, as shown by curve B. It will be seen that the force exertedon the briquettes exceedsthe critical value when the thickness of thebed amounts to 11 The curves approach asymtotically to a limiting value.As the distance between the partition walls further decreases, thislimiting value also decreases. At a distance of about 30 cm. thislimiting value is smaller than the critical value k Due to variation inthe strength of the briquettes, a certain safety-range has to be kept inmind. At the other end, obstruction may occur during filling or emptyingof the container. when the distance between the partition walls is madetoo small. In view of this, a distance of 20-25 cm. is preferred. Therelation between K and H in such a case corresponds to curve C, in whichcase the thickness of the bed may have any value without danger ofdamaging the briquettes, as the asymtotic value is substantially lowerthan the critical value k Mounted under the filling opening 10 are threegrates 14, 15, and 16 arranged in spaced-apart, step-wise relationship,one generally parallel to the other. The briquettes supplied through theopening 10 thereby roll over the-grate 14, thence fall onto the grate15, and roll off onto the grate 16, and onto the grate or bottom wall 9.

In order to reduce the rate of fall of the briquettes over the loweredges of the grates 14, 15, 16, there are provided suspended chains 17,18, and 19, hung adjacent to the bottom edge of the grates 14, 15, and16, respectively. By virtue of this arrangement, as the container 4 isprogressively filled, the upper part of the container 4 is filled bybriquettes rolling over the back edges of the grates 14, 15, and 16,thereby falling within the maximum allowable height in order to preventdamage to the briquettes.

A suitable cover plate 20 at the top of the apparatus provides access tothe interior thereof and is normally closed when the blower 2 and theburner 3 are put into operation.

The combustion gas, with an excess of. air, flows through the bed ofbriquettes thereby raising the temperature thereof and startingoxidation. Subsequently, the burner 3 is put out of operation and air isintroduced into the gas flow through the conduit 7 in order to completethe oxidation. During the oxidation process the temperature of thebriquettes is maintained for a predetermined period of time at thedesired value generally between 200 and 400 C. by introducing water intothe gas flow through the conduit 8. At the end of the oxidation periodthe briquettes are cooled by introducing water into the gas flow throughsprayers 21 and subsequently by spraying the briquettes directly throughsprayers 22 mounted above the bed of the briquettes. Suitable valves(not shown) may be mounted in conduits 7 and 8 for controlling theamounts of air and water introduced into the gas flow. Mounted adjacentthe lower end of the container 4 is a bottom closure plate 23 secured inan 'will be apparent to those skilled in the art.

'to below 0.3% of the total charge.

opening 24 by anysuitable means (not shown). A conveyor 2-5 isoperatively disposed below the opening 24 for carrying away thebriquettes which are normally discharged from the container i by openingthe valve 23 after the briquettes have been cooled.

Referring now to FIGURE3, there are shown grates 26 operatively mountedbelow the filling opening of the container 4 so that the lower edge ofone grate is mounted transversely adjacent the top portion of anadjacent grate. By virtue of this arrangement the briquettes fallthrough the space therebetweenon the bottom grate 9 at a relatively lowspeed. Mounted beneath the greate 9 are a plurality of bars 27 havingpins 28 projecting from their lower ends upwardly through the openingsin the grate 9. The bars, 27, in turn, are mounted for pivotablemovement about the pivots 29 mounted in the casing or the like by anysuitable means (not shown). In this embodiment of the inventiomthebriquettes rolling down along the bottom of the grate strike the pins 28thereby reducing the speed at which they strike the lower end of thecontainer to allowable values. When the layer reaching the lower edge ofthe lowest grate 27 has been formed on the bottom wall 9, the height ofthe briquette bed in the chute formed by the grates 26 will increaseuntil the briquettes flow over the upper edge of the lowest grate 26into the box 4, filling the same. The pins 28 then are of no utility andmay be removed from the briquette bed by pivoting the bar downwardsabout the pivots 29. If desired, the operating mechanism for the bars 28may be constructed so that the bars 28 can be completely removed fromthe conduit 1.

Turning now to FIGURE 4, a row of chains or similar flexible elements 30are suspended into the container 4 through the filling openinglt). Byvirtue of this arrangement, immediately after the first briquettes havebeen filed into the box, a thin layer 311 of briquettes is formed infront of the chains, the layer 31 breaking the fall of the followingbriquettes. Subsequently, the briquettes pass under the chains 30,rolling down the grate 9 at an allowable speed. If desired, this speedmay be reduced even further by means of brake chains 32 suspended in thebox by any suitable means (not shown). After the container 4 has beenfilled, the chains 30 are removed by winding them onto a drum 33, afterwhich, the opening 10 is closed by the cover plate 20.

Suitable modifications to the invention defined herein For instance, thedirection of the gas flow may be such that the gases are introduced intothe upper side of the briquette bed and discharged by the bottom grate9. Furthermore, the cooling of the briquettes may take place outside theapparatus.

Treatment of briquettes according to this invention can restrict thepercentage of dust and damage of briquettes Thus, if the bottom grate 9is substantially parallel to the natural slope of the briquettes, thefree surface of the briquettes is substantially parallel to the bottomwall of the container 4 when the latter has been filled according tothis invention, the requirement of a constant bed thickness therebybeing obtained. The natural slope of the briquettes having theconventional oval shape is 3540, and suitable means for altering theangle between the box and the horizontal may be provided. If the coalbriquettes are uniform and rounded, the naturalslope can be ratheraccurately determined beforehand.

By virtue of this invention, the container 4 can be filled to a constantbed thickness simply by supplying the briquettes through the opening 10by a funnel or the like. By virtue of the sloping position of the bottomwall 9, the container 4 can be emptied upon completion of the treatmentof the briquettes through the opening 24 in the end wall without thenecessity for special devices.

Likewise, the rate of travel of falling briquettes is successfullyreduced by the provision of the suspended chains a? u 30, 32, causingformation of a thin layer of briquettes under the fillingopening 10,this layer breaking the fall of the falling briquettes.

As is apparent, the danger of the briquettes breaking is greatest withthe first briquettes which fall on the bottom grate 9 when empty androll down along the surface. Once a layer has been formed, however, thefall is broken and the speed with which the briquettes roll isconsiderably reduced.

From the foregoing description of the various embodiments of thisinvention, it is evident that the objects of this invention, togetherwith many practical advantages, are successfully achieved. Whilepreferred embodiments of my invention have been described, numerousfurther modifications may be made without departing from the scope ofthis invention.

Therefore, it is to be understood that all matters herein set forth orshown in the accompanying drawings are to be interpreted in anillustrative, and not in a limiting sense.

What is claimed is:

1. Apparatus for treating coal briquettes and the like comprising: apassage for circulating a gas in a closed circuit, an elongatedcontainer disposed within the passage,

.said container having side walls and a perforated bottom must flowthrough said container, said perforated bottom wall sloping downwardalong the length of said container at an angle to the horizontalsubstantially corresponding to the natural slope of the briquettes to betreated, filling means for filling said container with briquettes, saidfilling means being disposed adjacent the upper end of said perforatedbottom wall, means to relieve the static pressure on the briquettes, anddischarge means for discharging briquettes from said container, saiddischarge means being disposed adjacent the lower end of said perforatedbottom wall, and gas circulating means for circulating treating gas in aclosed circuit through the passage, through said perforated bottom wall,and through said container for treating the briquettes in the container.

.2. Apparatus as defined in claim 1 wherein said means to relieve thestatic pressure on the briquettes comprises a plurality of spaced apartvertical partition walls disposed in said container andarranged parallelto the side walls thereof, the partition walls being of a height andspacing such that the force exerted by the weight of the bed of thebriquettes on the lower layers of briquettes does not exceedsubstantially the breakage strength of the briquettes at the elevatedtemperature of the gas treatment, and the resistance to gas flow issubstantially equal throughout the area of the passage occupied by thecontainer.

3. Apparatus defined in claim 1 including means for changing the angleof said container bottom wall with respect to the horizontal.

4 Apparatus defined in claim 2 wherein the distance between saidpartitions is 20-25 cm.

5. Apparatus defined in claim 1 including means for reducing the rate oftravel of briquettes during filling of said container.

6. Apparatus defined in claim 5 wherein the means for reducingthe rateof travel of the briquettes includes.

the underside of said container, and means for operatively moving saidpins into and out of the perforated bottom wall of said container.

8. Apparatus defined in claim 5 including grates mounted between saidfilling means and said bottom wall, said grates being constructed andarranged to allow the container is being filled.

335,616 References Cited by the Examiner UNITED STATES PATENTS 5 5 51/21 Lovejoy -1 44-11 333,020 7/39 Karrick 20215 750,366 11/50 Wallace202-129 7/51 Huff 20215 10 7/56 Becker 202-23 FOREIGN PATENTS MORRIS O.WOLK, Primary Examiner.

JULIUS GREENWALD, Examiner.

1. APPARATUS FOR TREATING COAL BRIQUETTES AND THE LIKE COMPRISING: APASSAGE FOR CIRCULATING A GAS IN A CLOSED CIRCUIT, AN ELONGATEDCONTAINER DISPOSED WITHIN THE PASSAGE, SAID CONTAINER HAVING SIDE WALLSAND A PERFORATED BOTTOM WALL, SAID CONTAINER EXTENDING ACROSS THE ENTIREAREA OF THE PASSAGE SUCH THAT A GAS CIRCULATING THROUGH THE PASSAGE MUSTFLOW THROUGH SAID CONTAINER, SAID PERFORTED BOTTOM WALL SLOPING DOWNWARDALONG THE LENGTH OF SAID CONTAINER AT AN ANGLE TO THE HORIZONTALSUBSTANTIALLY CORRESPONDING TO THE NATURAL SLOPE OF THE BRIQUETTES TO BETREATED, FILING MEANS FOR FILLING SAID CONTAINER WITH BRIQUETTES, SAIDFILLING MEANS BEING DISPOSED ADJACENT THE UPPER END OF SAID PERFORATEDBOTTOM WALL, MEANS TO RELIEVE THE STATE PRESSURE ON THE BRIQUETTES, ANDDISCHARGE MEANS FOR DISCHARGING BRIQUETTES FROM SAID CONTAINER, SAIDDISCHARGE MEANS BEING DISPOSED ADJACENT THE LOWER END OF SAID PERFORATEDBOTTOM WALL, AND GAS CIRCULATING MEANS FOR CIRCULATING TREATING GAS IN ACLOSED CIRCUIT THROUGH THE PASSAGE, THROUGH SAID PERFORATED BOTTOM WALL,AND THROUGH SAID CONTAINER FOR TREATING THE BRIQUETTES IN THE CONTAINER.